Epilobium angustifolium, also known as fireweed, is a perennial herbaceous plant in the willowherb family Onagraceae. It is native throughout the temperate Northern Hemisphere. Analysis of Epilobium angustifolium extract has determined there are three major polyphenol groups in this ingredient: tannins (oenothein B), phenolic acids (gallic and chlorogenic acids) and flavonoids. These components all have antioxidant activity. Antioxidants limit oxidative damage caused by free radicals, the unstable molecules that contribute to the formation of premature wrinkles and fine lines on the skin. In vivo testing also revealed that Epilobium angustifolium extract protects the skin from UV-induced erythema (redness). For these reasons, Epilobium angustifolium extract is an excellent ingredient for anti-aging skin care products.

Epilobium angustifolium extract also has very strong anti-inflammatory and antimicrobial effects. This ingredient can be used to calm skin irritation and inflammation, and is especially beneficial for those with sensitive skin.